Though I live in madison, I didn't want to bug andy at YJ with possibly redundant questions about 3rensho. I wondered if any info exists as to who was building at 3rensho and when...And were there time periods (or just serial number ranges) when Konno was building more?

To me, it seems like dropping a hefty amount of cash on 3rensho is silly, if the frame in question was likely built when Makino or Yamaguchi were building for 3rensho (and you could buy one of their current frame-lines for much less).